Developmental dysplasia of the hip

Pelvic rotation and tilt can cause misinterpretation of the acetabular index measured on radiographs

BACKGROUND

Radiographic diagnosis and followup studies of developmental dysplasia of the hip are commonly performed by measuring the acetabular index on radiographs using Hilgenreiner's method. The outcome of the measurement, however, depends on the orientation of the subject's pelvis relative to the xray source. The influence of pelvic rotation and tilt on the measurement error has been evaluated separately but not in combination.

QUESTIONS/PURPOSES

We asked whether (1) combinations of pelvic rotation and tilt introduced systematic error in acetabular index measurement in a reproducible way, and (2) ratios proposed to evaluate either pelvic rotation (R(rotation)) or pelvic tilt (R(tilt)) are influenced by pelvic tilt and rotation, respectively.

METHODS

Radiographic measurements of the acetabular index, R(rotation), and R(tilt) were performed on digitally reconstructed radiographs of one high-resolution three-dimensional CT dataset with various combinations of pelvic rotation and tilt.

RESULTS

For rotations and tilt up to 12°, the average systematic errors in the acetabular index varied from -8.8° to 4.5°. Negative and positive error values can be interpreted as underestimations and overestimations of the acetabular index, respectively. Errors in acetabular index measurements were acceptable for R(rotation) values between 1.0 and 2.0 and R(tilt) values between 1.1 and 1.8.

CONCLUSIONS

To limit the systematic error in assessing the acetabular index caused by pelvic misalignment, we recommend only radiographs acquired with ± 4° rotation and ± 4° tilt be considered acceptable.

Newborns with sonographically dysplastic and potentially unstable hips: 6-year follow-up of an RCT

OBJECTIVE

To examine the long-term outcome of early abduction splinting versus active sonographic surveillance in newborns with mildly dysplastic hips.

PATIENTS AND METHODS

Between 1997 and 2003, 128 newborns with mildly dysplastic and potentially unstable hips on ultrasound (43° ≤ α-angle < 50°) were randomly assigned to immediate abduction treatment or sonographic surveillance. All were invited for a radiographic follow-up at 6 years. The radiographs were analyzed by a single radiologist masked to the randomization allocation, and markers of hip dysplasia (acetabular index, center-edge angle of Wiberg) and avascular necrosis were reported.

RESULTS

Eighty-three participants (65%) agreed to participate in the follow-up (42 participants from the treatment group). The mean acetabular index was 14.7° (SD: 5.6°) for the treatment group and 13.9° (SD: 3.9°) for the control group (mean difference: -0.8° [95% confidence interval: -2.9° to 1.3°]). Values were within normal ranges for age for all participants except for 1 female subject from the treatment group. The mean center edge was 26.6° for those treated and 26.4° for the active surveillance group (mean difference: -0.3° [95% confidence interval: -2.5° to 2.0°]). None had markers suggestive of avascular necrosis.

CONCLUSIONS

We found no difference in radiographic outcome at 6 years of age between children allocated to initial splintage for 6 weeks and those offered active sonographic surveillance. The delayed acetabular ossification or persistent dysplasia seen in a third of infants from both groups at 1 year of age had completely resolved in all but 1 of the female subjects from the treatment group.

Association of interleukin-6 and transforming growth factor-β1 gene polymorphisms with developmental hip dysplasia and severe adult hip osteoarthritis: a preliminary study

Developmental hip dysplasia (DDH) greatly contributes to occurrence of severe hip osteoarthritis (OA) in adulthood, but the association between the two is not a perfect one. Both conditions are known to have a strong genetic component. Transforming growth factor β1 (TGF-β1) and interleukin-6 (IL-6) are two pro-inflammatory cytokines included in pathogenesis of OA, bone remodeling and development of bone and joint tissues. TGF-β1 gene has a polymorphic site in the signal sequence ((29)T→C) and "C allele carriage" is associated with higher circulating TGF-β1 levels. IL-6 gene has several polymorphic sites in the promoter region including -572T→C transition associated with higher circulating IL-6 levels. As a preliminary investigation on possible association between these polymorphisms and severe adult hip OA secondary to DDH, 28 consecutive patients and 20 healthy controls were genotyped at these loci. With adjustment for sex, "C allele carriage" in the TGF-β1 signal sequence and CC genotype ("transition homozygous") at locus -572 in the IL-6 promoter were each associated with severe OA secondary to DDH (OR=13.4, p=0.016 and OR=6.2, p=0.024, respectively). The combination of these genotypes was particularly strongly associated with the disease (OR=11.1, p<0.001). Data support feasibility of larger-scale studies on potential association between TGF-β1 signal sequence and IL-6 promoter polymorphisms and occurrence of DDH and (un)related severe OA.

Total hip replacement with an uncemented Wagner cone stem for patients with congenital hip dysplasia

PURPOSE

The purpose of this study was to review retrospectively the cases operated upon in our department in recent years with a Wagner stem and a small socket in cases of Crowe I or II dysplastic hips.

METHODS

We conducted a retrospective clinical radiological review of 30 hips diagnosed with hip dysplasia Crowe I or II treated in our centre between 2002 and 2008. All of them were treated with a Wagner cone stem and a small Trilogy acetabulum (Zimmer ®).

RESULTS

There were 15 men and 11 women with 13 left and 17 right femurs. Mean follow-up was 43.44 months (range 14-87). Eight patients were Crowe I type and 22 were Crowe II type. Merlé d'Aubigne score pre-operatively was 12.23 and at the last follow-up was 15.54. Mean leg length inequality was 1.79 and after surgery it was 0.69 cm. Complications included three infection and three dislocations (two of them in the same patient).

CONCLUSIONS

The use of a Wagner stem is a good option to correct the different deformities in the proximal femur in these cases. A small socket allows a correct relocation of the acetabulum in a dysplastic socket with good bone coverage.

Developmental dysplasia of the hip - angle trends after operation in different age groups

INTRODUCTION

The aim of our study was to evaluate changes in collodiaphyseal, Hilgenreiner and Wiberg's centre-edge angle values in different age groups of children before and after surgical correction of developmental dysplasia of the hip.

MATERIAL AND METHODS

We evaluated 78 children with developmental hip dysplasia treated at University Children's Hospital in Belgrade during a 10-year period. Three age groups were analysed: the first group younger than 24 months of life, the second group between 25 and 48 months, and the third group older than 48 months of life. Three angles were evaluated separately before and after surgical correction: collodiaphyseal angle, Hilgenreiner angle and Wiberg's centre-edge angle.

RESULTS

We found a highly statistically significant difference (p < 0.001) before and after the operation for collodiaphyseal and Hilgenreiner angle in the first and second age group, while there was a statistically significant difference (p < 0.05) in the third age group. Regarding Wiberg's centre-edge angle, there was a highly statistically significant difference (p < 0.001) in all age groups. One way ANOVA revealed a highly statistically significant difference (p < 0.001) for collodiaphyseal and Hilgenreiner angle in age groups before the operation, while after surgery such a trend remained for Hilgenreiner angle. Regarding collodiaphyseal and Wiberg's centre-edge angle in the period after correction, there was no statistical difference (p > 0.05) between age groups of the participants.

CONCLUSIONS

Our findings demonstrate that age of participants is in correlation with correction of values for collodiaphyseal angle, Hilgenreiner angle and Wiberg's centre-edge angle in surgically treated children diagnosed with developmental dysplasia of the hip.

Evaluation of a training program for general ultrasound screening for developmental dysplasia of the hip in preventive child health care

BACKGROUND

A research study in the Netherlands showed that general ultrasound (US) screening was cost-effective in the detection of developmental dysplasia of the hip (DDH). This study was followed by a pilot implementation study. Part of this pilot implementation study is to investigate whether professionals of the infant health care (IHC) system, with no previous US experience, would be able to perform US of the hip.

OBJECTIVE

This study looks at health care worker ability to classify US images into a modified Graf system.

MATERIALS AND METHODS

After theoretical and practical training, seven nurses and physicians of the participating IHC centers reported their findings on sonographic images of 80 children. This was repeated five months later. From the two evaluation moments the intraobserver agreement and the interobserver agreement was determined.

RESULTS

The average estimated interobserver Cohen's kappa for both sessions was for nurses 0.6 and for physicians 0.5. The second evaluation showed a decrease from an average of 4.3% missed cases per screener to 2.3% and an increase of an average of 5% false positives per screener to 9.1%.

CONCLUSION

The inter- and intra-observer agreement is comparable to similar studies in which the participants had a professional background in US examination. The level of agreement of the trainees in the perspective of the screening process was considered sufficient for the pilot implementation project.

Ultrasound in developmental dysplasia of the hip: A screening study in Sardinian newborns

INTRODUCTION

Developmental dysplasia of the hip (DDH) is the most frequent inborn deformity of the locomotor apparatus. Ultrasound screening is frequently used to identify DDH in view of the brevity of the preclinical period during which diagnosis is possible. Appropriate therapeutic intervention during this period can positively affects the evolution of the disorder.

METHODS

An unselected population of 1158 Sardinian neonates underwent ultrasound examinations of both hips, and findings were classified according to the method described by Graf. Patients were assessed by means of retrospective analysis to reveal cases of congenital dislocation of the hip joint. All cases were classified and treatment outcomes determined.

RESULTS

A total of 145 hips requiring treatment were observed in 122 children. Hip dysplasia and/or dislocation were diagnosed between the ages of 14 days and 3 months. One month after diagnosis ultrasound findings were normal in 94% of the infants with at least one hip classified as type 2a. The remaining 6% were classified as types 2b, 2c, D, and 3. All were treated with abduction splints, and normal hip development was observed after one or two months of treatment. Type 4 hips were referred to an orthopedic surgeon for specialist treatment.

CONCLUSIONS

When performed by skilled operators, ultrasonographic techniques are of considerable value in prescribing treatment for DDH. The satisfactory prognosis associated with early treatment of severe congenital dislocation of the hip joint underlines the advisability of scheduling routine hip screening programs to ensure early diagnosis and effective treatment of the disorder.

The effectiveness of a programme for neonatal hip screening over a period of 40 years: a follow-up of the New Plymouth experience

Since September 1964, neonates born in New Plymouth have undergone clinical examination for instability of the hip in a structured clinical screening programme. Of the 41 563 babies born during this period, 1639 were diagnosed as having unstable hips and 663 (1.6%) with persisting instability were splinted, five of which failed. Also, three unsplinted hips progressed to congenital dislocation, and there were four late-presenting (walking) cases, giving an overall failure rate of 0.29 per 1000 live births, with an incidence of late-walking congenital dislocation of the hip of 0.1 per 1000 live births. This study confirms that clinical screening for neonatal instability of the hip by experienced orthopaedic examiners significantly reduces the incidence of late-presenting (walking) congenital dislocation of the hip.

Association of oestrogen receptor gene polymorphism with the long-term results of rotational acetabular osteotomy

Acetabular dysplasia (AD) contributes to the development of osteoarthritis of the hip. A rotational acetabular osteotomy (RAO) is one of the methods of pelvic osteotomy to prevent or treat secondary osteoarthritis of the hip. Although most of the patients that undergo RAO show satisfactory results, some have poor results. This study investigated whether gene polymorphisms of both the vitamin D receptor (VDR) and oestrogen receptor (ER) are involved in both AD and the postoperative results following RAOs. Sixty-four Japanese patients with AD who were treated by an RAO were enrolled in this study (59 women and 5 men, aged 13-59, with an average age of 40.3). Gene polymorphisms of the VDR [ApaI and TaqI restriction fragment length polymorphisms (RFLPs)] and ER (PvuII and XbaI RFLPs) were determined in these patients. The relationship between both the AD and radiographic postoperative changes of the hip joint after an RAO with these gene polymorphisms were examined. The frequencies of ER gene polymorphism coded as pp (RFLP/PvuII) in patients with AD were statistically significantly different (p = .011) from those coded as both PP and Pp. The joint space width narrowed even after RAO in 90% of the patients with the pp gene polymorphism, while it narrowed in only 35% of the patients with either PP or Pp seven years or longer after an RAO. The PvuII polymorphism in the ER gene was associated with the postoperative result of an RAO, while no association was observed between the AD with VDR and ER gene polymorphisms.